This invention relates to a hand-held device for treating small surface areas, specifically tooth faces in a patient's mouth, with a jet of pressurized air containing particles of an abrasive material.
A device of this kind is known from U.S. Pat. No. 4,776,794, which employs an abrasive liquid. The known device cannot be operated with sand, powder or a powdery mixture as is required for producing a highly efficient abrasive jet.
DE-A1-3,727,441 describes a dental sand blasting apparatus with a stationary portion including a vibrator operated by pressurized air for preparing a sand-air mixture. The mixture is supplied via a hose to a discharge nozzle formed on a hand-held part. The overall apparatus is expensive and bulky.
Another sand blasting device is shown in DE-A1-3,634,700 wherein a sand container is rigidly connected with a nozzle head and the sand is sucked from the container by jet action exerted on the upper end of a downtake. In operation of this device, care must be taken that the downtake is always submerged by the sand. Therefore, the device may not be held in any desired orientation and is therefore not readily suited for treating surface areas which are difficult to access, such as locations in a patient's mouth. Moreover, the downtake requires a certain minimum cross-section for sucking the sand and is therefore unsuited to produce a very fine sand-blasting jet for treating minute surface areas, such as faces of a tooth.